Antenna



FIG. 1 is a top plan view of an antenna, showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a top perspective view thereof;

FIG. 5 is a top plan view thereof, with the unclaimed environment not shown; and,

FIG. 6 is a front elevation view thereof, with the unclaimed environment not shown.

The broken lines show unclaimed environment only and form no part of the claimed design. 

CLAIM The ornamental design for an antenna, as shown and described. 